The use of a miter cut to join two pieces of wood has been well-known for centuries. A miter cut may be linear or non-linear. It is also known to use a combination of a linear and non-linear cut to form a miter joint. Such a joint is identified in Webster's New Collegiate Dictionary, G. and C. Merriam Company, Springfield, Mass. 1981, at page 731, as a rabbeted miter joint. Such a joint, however, has not been used in hollow window frame constructions for multi-component corner joints.
U.S. Pat. No. 2,701,397 (Perkins) shows a construction for a storm window frame which includes a diagonal cut at the inside corner of the joint, which cut forms only a portion of the joint. However, the rest of the joint does not meet face-to-face, but rather overlaps.
U.S. Pat. No. 2,874,420 shows a metal door frame. Again, there is a diagonal cut from the inside corner of the joint, which cut forms the major portion of the joint. The remaining portion of the joint is a curved cut ending along the outside face of a lateral surface of the door frame, not at the apex of the outside corner. This joint is designed for a door frame with the corner construction configured to allow the frame members to swing from an acute angle to a right angle position and to maintain the right angle by a snap together joint.
It is an object of the invention to provide a window frame having strong joints.
Another object of the invention is to provide a window frame having joints that fit together easily in precise relationship.
Another object of the invention is to provide a window frame having joints that are easily assembled without lateral or diagonal misalignment to assure a square sash assembly.
Another object of the invention is to provide a window frame having joints that will not rack and twist.
Another object of the invention is to provide a window frame having joints that can be tightly sealed.
Another object of the invention is to provide a window frame that is capable of providing a leakproof seal between the frame and the window it captures.
Another object of the invention is to provide a window frame having the capacity to channel moisture away from damaging contact with the sealing components to prevent sealant failure.
It is still another object of the invention to provide a window frame having an increased capacity for insulation.